Whoa, hold on! By volume? Aren't you supposed to be doing this by weight? Well, yes. But in the amounts I am mixing (5-7 Litres on average) the difference is very small. For the application (looking at appearance) the exact cement content isn't crucial.

It becomes crucial for the crush test cylinders (another topic for another post.)

From these pictures it becomes apparent that rammed earth can come in a wide variety of finishes and colors.

If I was going to be the head of a rammed earth builders guild or association, one of the first things I would do would be to create a library of possible rammed earth mixtures for my given region. I would make the blocks, collect the particle size distribution data, and do the crush tests. All that data should be collected. Clients and interested owner/builders should be able to look at as gigantic an assortment of rammed earth mixtures as they could paint chips. And that book of "paint chips" should be on the web, available for EVERYONE who is interested.

Certainly I'm not the first one to think of this. Certainly something like this already exists.